What is Brachycephalic Obstructive Airway Syndrome?

1st November 2022

Brachycephalic Obstructive Airway Syndrome (BOAS for short) is the name given to a set of breathing problems that can occur in breeds of dog that have very short, “squashed” faces. Examples of these breeds are English and French Bulldogs and Pugs.

Why does BOAS occur?

Many dogs of these short-faced breeds have difficulty breathing because the shape of their skull means that they have:

Narrow nostrils
Overlong soft palate (at the back of the throat)
Narrow windpipe
Swollen larynx (voicebox)

These features narrow the airway (as if the dog is trying to breathe through a narrow straw).

What are the symptoms of BOAS?

Affected dogs will have noisy breathing (worse when excited or exercising) and often snore when they are asleep. Some dogs have to make such an effort to suck air through the narrow passageways when they breathe, that they suck stomach acid up into the food passage, causing gulping, burping, retching and vomiting. More severely affected dogs may be reluctant to exercise, or will collapse during exercise. Hot weather makes everything worse.

What can we do about BOAS?

Dogs with BOAS should avoid strenuous exercise, particularly in hot weather. Using a harness instead of a collar and keeping dogs at a lean body weight are also helpful.

However, surgery is the treatment of choice when dogs cannot breathe properly. Excess tissue can be surgically removed from the nostrils and soft palate, improving air flow.

In general, the earlier the surgery is performed (ideally before 2 years of age), the better the outcome as this condition worsens over time. Affected dogs should not be used for breeding so that we can reduce the number of dogs being born with these problems in the future. Sometimes surgery can be carried out at the same time as neutering.

BOAS surgery should be carried out by experienced surgeons with good facilities for supporting patients through the surgery and recovery period.